Frictional rolling contact between a bowling ball and a lane often leaves irregular wear portions or scratches on a surface of the bowling ball. In particular, the bowling ball tends to make contact with the lane substantially at the same circumferential area thereof, which may cause unbalanced wear of the bowling ball. The scratched or unevenly worn bowling ball looks ugly and use of the scratched or unevenly worn bowling ball makes it difficult for a bowler to exercise, e.g., spin skills at his or her desire due mainly to the unpredictable movement of the bowling ball. As a result, the scratch and the unbalanced wear may adversely affect the score of a bowling game, thus reducing amusement of the game played. Thus, the bowling ball needs to be periodically abraded into a perfect spherical shape with no or little scratch.
There are a number of prior art references that disclose a device for automatically abrading a bowling ball. One of them is U.S. Pat. No. 5,613,896 that teaches a bowling ball resurfacing machine including three shafts disposed at an angle of 120 degrees in such a manner as to support a bowling ball, three motors for rotating the corresponding shafts in a forward or reverse direction, and three cone-shaped abrading cups mounted on the shafts. Although this bowling ball resurfacing machine has its own advantages, it suffers from a drawback in that a rolling direction or a rotation axis of the bowling ball cannot be vigorously changed during a resurfacing process. For this reason, the bowling ball resurfacing machine encounters a difficulty in uniformly abrading the whole surface of the bowling ball into a perfect sphere.
Another prior art reference is U.S. Pat. No. 7,063,607 disclosing a bowling ball resurfacing apparatus that includes a housing, first and second vertical support rollers mounted to the housing for rotation about parallel vertical axes, each of the vertical support rollers adapted to make contact with the surface of the bowling ball at one lateral bottom side of the bowling ball, first and second horizontal support rollers mounted to the housing for supporting the bowling ball in cooperation with the vertical support rollers, each of the horizontal support rollers rotatable about horizontal axes and adapted to make contact with the surface of the bowling ball at the other lateral bottom side of the bowling ball, drive motors for causing the support rollers to rotate, and a grinding-and-polishing wheel assembly for making frictional contact with the surface of the bowling ball to grind or polish the bowling ball.
The prior art devices noted above are capable of substantially evenly abrading or polishing the surface of the bowling ball by rotating the bowling ball in different directions. However, the prior art devices leave a room for improvement because they are structurally complicated, difficult and costly to fabricate, and highly susceptible to trouble.